Various types of hearing prostheses provide persons with different types of hearing loss with the ability to perceive sound. Hearing loss may be conductive, sensorineural, or some combination of both conductive and sensorineural. Conductive hearing loss typically results from a dysfunction in any of the mechanisms that ordinarily conduct sound waves through the outer ear, the eardrum, or the bones of the middle ear. Sensorineural hearing loss typically results from a dysfunction in the inner ear, including the cochlea where sound vibrations are converted into neural stimulation signals, or any other part of the ear, auditory nerve, or brain that may process the neural stimulation signals.
Persons with some forms of conductive hearing loss may benefit from hearing prostheses, such as acoustic hearing aids or vibration-based hearing aids. An acoustic hearing aid typically includes a small microphone to detect sound, an amplifier to amplify certain portions of the detected sound, and a small speaker to transmit the amplified sounds into the person's ear. Vibration-based hearing aids typically include a small microphone to detect sound, and a vibration mechanism to apply vibrations corresponding to the detected sound to a person's bone, thereby causing vibrations in the person's inner ear, thus bypassing the person's auditory canal and middle ear. Types of vibration-based hearing aids include bone anchored hearing aids, direct acoustic cochlear stimulation devices, or other vibration-based devices. A bone anchored hearing aid typically utilizes a surgically-implanted mechanism to transmit sound via direct vibrations of the skull. Similarly, a direct acoustic cochlear stimulation device typically utilizes a surgically-implanted mechanism to transmit sound via vibrations corresponding to sound waves to generate fluid motion in a person's inner ear. Other non-surgical vibration-based hearing aids may use similar vibration mechanisms to transmit sound via direct vibration of teeth or other cranial or facial bones.
Persons with certain forms of sensorineural hearing loss may benefit from cochlear implants and/or auditory brainstem implants. For example, cochlear implants can provide a person having sensorineural hearing loss with the ability to perceive sound by stimulating the person's auditory nerve via an array of electrodes implanted in the person's cochlea. An external component of the cochlear implant detects sound waves, which are converted into a series of electrical stimulation signals delivered to the implant recipient's cochlea via the array of electrodes. Auditory brainstem implants use technology similar to cochlear implants, but instead of applying electrical stimulation to a person's cochlea, auditory brainstem implants apply electrical stimulation directly to a person's brain stem, bypassing the cochlea altogether. Electrically stimulating auditory nerves in a cochlea with a cochlear implant or electrically stimulating a brainstem can help persons with sensorineural hearing loss to perceive sound.
The effectiveness of any of the above-described prostheses depend not only on the design of the prosthesis itself but also on how well the prosthesis is configured for or “fitted” to a prosthesis recipient. The fitting of the prosthesis, sometimes also referred to as “programming” or “mapping,” creates a set of configuration settings and other data that defines the specific characteristics of the stimulation signals (acoustic, mechanical, or electrical) delivered to the relevant portions of the person's outer ear, middle ear, inner ear, auditory nerve, brain stem, etc. This configuration information is sometimes referred to as the recipient's “program” or “MAP.”
Hearing prostheses are usually fitted to a prosthesis recipient by an audiologist or other similarly trained professional who may use a sophisticated fitting program to individually set multiple stimulation signal levels for multiple channels of the hearing prosthesis. Although sophisticated fitting programs may give an audiologist or other similarly trained professional a great deal of control and flexibility over the hearing prosthesis fitting parameters, fitting a prosthesis to a recipient with these sophisticated fitting programs can be complicated and time consuming even for trained professionals.